Oven



Dec. 16; 1924.

J. C. W'OQDSON OVEN Filed Dec. 13, 1922 3 Sheets-Sheet 1 INVENTOR James CIWoodson.

WITNESSES: 5% M4 $6745 ATTRNEY Patented files. 16,

UNITED aranr JAMES C. WOODSON, 9F EAST PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTING- 'HO'USE ELECTRIC & MANUFACTURING CQMPANY, A CGRPORATION OF PENNSYL- VANIA.

OVEN.

application filed December 13, 1922.

To all whom it may concern:

Be it known that 1, JAMES C. VVoonsoN, a citizen of the United States, and a resident of East Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Ovens, of which the following is a specification.

My invention relates to ovens and particularly to ventilated ovens.

One object of my invention is to provide a relatively simple construction for an oven, comprising inside and outside skeleton frames and a plurality of heat insulating wall panels held thereby.

Another object of my invention is to 1ro vide an electrically heated oven with means for removing heavy gases produced by japanned or enameled objects placed therein, while maintaining a flow of air through the oven that shall insure a substantially even temperature throughout the oven chamher.

In practicing my invention, I provide an inside skeleton frame comprising angle bars and members of channel section, against which is held a plurality of heat-insulating panels enclosing an oven chamber. A plurality of electric heating elements are located at the sides of the oven chamber substantially co-extensive therewith. A solid protecting baflle is located at the outside of the heating elements, extending from the floor upwardly for a portion of the height of the heating elements, and a perforated baflle or screen extends upwardly therefrom and over the top of the heating elements. A perforated inlet air-conduit is located beneath each of the sets of heating elements adjacent the side walls of the oven. One end of each of the conduits extends outwardly through the rear panel, where it may be connected to a blower pipe or to the atmosphere. An outlet air-conduit, having side perforations only, is located on the floor centrally and longitudinally of the oven chamber and is connected to the suction pipe of the blower.

In the accompanying drawings,

Figure l is a View, in side elevation with certain portions of the furnace structure cut Serial No. 606,595.

away, of an oven embodying my invention,

Fig. 2 is a top plan view thereof,

Fig. 3 is a view, in rear elevation thereof, with a part thereof cut away, and

Fig. a is a fragmentary sectional view to illustrate the construction and arrangement of the bottom and side panels.

An oven 11, which is here illustrated is substantially rectangular in shape, comprises a plurality of top panels 12, rear panels 13, fioor panels 1s and side panels 15, all of these being heat-insulating panels, of substantially the same general construction. Each panel comprises an outer sheet metal wall 16, and an inner sheet metal wall 17, located in spaced relation, the space therebetween being filled with a quantity 18 of a suitable heat-insulating material, such as mineral wool. Any suitable or desired constructi-on to hold the sheet metal plates l6 and 17 may be employed and l have indie-as ed, in Fig. 4, of the drawings, one of the methods which may be employed and which comprises providing each of the plates with laterally extending and co-operating flange portions.

The bottom panels M are provided with laterally extending members 19, of channel section, located between and suitably secured to the sheet metal plates 16 and 17, as sub stantially the entire weight of the rest of the oven structure is carried by these panels. The bottom sheet metal plate 16 extends beyond the edge of the panel and is provided with a small upturned flange portion 21, the construction forming a member of channel section, into which the lower edge of the side panels 15 extend in order to provide an interlock between the side and the botton'i panels.

An inner skeleton frame work comprises longitudinally extending angle bars 22 located at the top and the bottom edges of the side panels and vertically extending angle bars 23 at each side of the oven, gusset plates 2% being employed to secure the members together. Horizontally and laterally extending angle bars have their ends secured to the angle bars and 23 by the same gusset plates 2st. The bottom members of the inner skeleton frame work are constituted by members 26 of channel section which extend horizontally and laterally of the oven and which are suitably connected to the respective members 22 and 23 by gusset plates 27.

The hereinbefore described construction of longitudinally extending angle bars, the vertically, and the horizontally and laterally extending angle bars and the members of channel section constitute an open skeleton frame work substantially rectangular in contour against which the respective top, side and end panels may be located.

Means for holding the plurality of panels against the inner skeleton frame work comprise an outer skeleton frame work built up of longitudinally extending angle bar members 28 located at the top and at the bottom of the panels and connected by a plurality of laterally extending angle bars 29 located at the .top and bottom, the respective ends of which are connected by gusset plates 31 to the angle bars 28. At the bottom a plurality of members 32, of channel section, are suitably secured by bolts 33 to the members 26, the bottom panels 14 being located and clamped therebetween. At the front, a pair of heat-insulating door panels 34 are provided with suitable hinge members 35 to permit of their being opened and closed as required by the operation of the oven.

in biiiilding up the oven structure comprising the inner and the outer skeleton frame work and the plurality of heat-insulating panels, the members 32 of channel section are first placed upon a level floor surface in proper spaced relation relatively to each other, after which the floor panels 14 are located thereon. Then the inner skeleton frame work, as hereinbefore described, is built upon the floor panels, after which the side, rear and top panels may be placed in their proper operative positions against the inner skeleton frame work. Then the outer skeleton frame work is built up and placed in its proper operative position on the outside of the heat-insulating panels after which the door panels 34 may be placed in their proper operative position. The entire structure provides an oven which is sub stantially air tight.

A plurality of electrical heating elements 36 and 37 are located in superposed positions adjacent to the side walls of the oven, each of the heating elements being substantially co-ex-tiensive with the wall of the chamber. The heating elements 36 and 37 may be of any suitable or desired construction, but preferably embody a suitable metal frame work upon which a resistor member is insulatedly mounted, the frame work being secured against the vertically extending angle bars 23 by suitable angle members 38. I employ preferably relatively high and narrow heating elements in order that the amount of space occupied thereby at each side of the oven chamber may be as small as possible to provide a maximum possible space within the oven for receiving work or material to be heat treated.

A perforated air-inlet conduit 39 coextensive with the oven chamber is located under each of the heating elements 37 and com prises a sheet metal duct substantially square in lateral section, which is providedwith a plurality of perforations 41 in its upper surface, the perforations extending along the entire length of the member 39. A sheet metal baffle plate 42 is provided adjacent to the outside surface of the heating elements 36 and 3'? and has its lower edge operatively engaging the upper surface of the conduit 39. The baffle plate 42 extends upwardly along the outside of the heatingelements for at least one half of their height and a perforated bai'l'le or screen 43 extends to the top of the heating element and thereover against the side of the oven to protect the heating elements against damage by reason of objects falling thereon. The conduit 39 has its front end closed and its rear end ex tending outwardly through the rear panel 13 so that air may enter the duct.

An outlet air duct 44, substantially rectan ular in section and relatively wide and flat, is located within the oven chamber centrally thereof and extends longitudinally from the front of the oven structure to the rear thereof and through a suitable opening in the back panel 13 to the outside atmosphere.

Suitable clamping means 45 are provided to secure the outlet duct in its proper operative position on the floor of the furnace. A plurality of perforations 46 are provided in. the side walls of the dnct 44 and extend over substantially its entire length, through which air and gases are withdrawn from the oven chamber.

A blower 47 is mounted on asuitable supporting means 48 on the top of the oven structure and may be driven by a suitable electric motor 49. The structure 48 may comprise an enclosed sheet metal casing to which one end of a plurality of conduits 51 may be connected, the other end of each of which is suitably connected to the pro jecting end of the air inlet conduits 39. A. conduit has one of its ends connected to the projecting end of the outlet conduit 44 and has its other end connected to the blower 47. If desired, the blower may be provided with an exhaust conduit 53 connected to the casing 43, the amount of air which may leave therethrough being regulated by a damper having an operating lever If it is considered desirable to pro vide for either a forced circulation or a recirculation of air through the oven chamher, the lower end of the conduits 51 may be connected to a portion only of the conduit. 39, the other portion being open to the atmosphere.

It the blower is operated with the exhaust conduit open, heated air is withdrawn from the oven chamber through the outlet conduit 4.4 and is forced through the exhaust conduit into the outer air. Only a relatively small portion of the heated air from the chamber will be forced through the inlet conduits 51 and 39 back into the oven chamber, and therefore cold fresh air enters through the open portion of the conduit 39, to be heated by the heating elements 3'? and 35 to be exhausted through the out let conduit. This method therefore provides for a circulation of air through the oven chamber.

If a recirculation of air is desired, the damper 54 is closed, and the heated air is withdrawn from the furnace chamber through the outlet conduit l4 and is then forced by the blower through the inlet conduits 51 and 39 back into the oven chamber. It the conduit 39 is partly open to the outer air, a small quantity of fresh cold air is, of course, drawn into the oven chamber, but if this is undesirable, such opening may be closed.

An oven of this type is more particularly intended for use in drying enameled or japanned metal articles which are placed within the oven chamber mounted on suitable carriages adapted to hold the work with the least possible contact therewith. During the drying of such enameled or japanned metal articles, gases are produced which are heavier than air and these will flow or move downwardly and rest upon the floor of the oven chamber. The hereinbetore described construction, comprising air inlet conduits which force the incoming air to flow past the vertically extending heating elements which are enclosed over substantially the greater portion of their height, provides means for insuring that the incoming air shall flow upwardly into the furnace chamber before starting on its outward path.

With the hereinbetore described construction of heating elements and of the co-operating cold air inlets, the heavier-than-air gases hereinbefore described as being produced by the japanned articles will gather more particularly in the central portion of the chamber immediately above the floor thereof from which place they will be quickly removed through the outlet duct hereinbefore described.

The device embodying my invention thus provides a positive means for insuring a substantially uniform temperature through out the oven chamber and for causing substantially all of the volume of the chamber to be traversed by incoming heated air.

Various modifications and changes in. tail and arrangement may be made witn out departing from the spiritand scope of the invention, and such modifications are intended to be covered by the appended claims.

I claim as my invention:

1. In an oven, in combination, a skeleton frame-work, a plurality of heat-insulated panels secured to said frame-work and enclosing an oven chamber, and. electric heat-- ing elements supported by said frame-work adjacent the bottom of the sides of said turnace chamber.

2. In an oven, in combination, a skeleton frame-work, a plurality of heat-insulated panels secured to said frame-work and enclosing an oven chamber, electric heating elements supported. by said frame-Work adjacent the bottom of the sides of said turnace chamber, and air inlets for said oven located below said heating elements.

3. In an oven, in combination, a skeleton frame-work, a plurality of heat-insulated panels secured to said frame-work and enclosing an oven chamber, electric heating elements supported by said frame-work adjacent the bottom of the sides of said furnace chamber, air inlets for said oven located below said heating elements and an air outlet located on the floor of said oven and between said air inlets.

4. In an oven, in combination, a skeleton frame-work, a plurality of heat-insulated panels secured to said frame-work and onclosing an oven chamber, electric heating elements supported by said frame-work adjacent the bottom of the sides of said furnace chamber, air inlets for said oven located below said heating elements and an air out let located on the floor of said oven and between said air inlets, said air inlets and outlets being substantially co-extensive with the length of said furnace chamber.

5. In an oven, in combination, a skeleton frame-work, a plurality of heat-insulated panels secured to said frame-work and enclosing an oven chamber, electric heating elements supported by said frame work adjacent the bottom of the sides of said furnace chamber, air inlets under said heating elements substantially co-extensive therewith, and means adjacent said heating elements for deflecting the incoming air upwardly past said heating elements.

6. In an oven, in combination, an extended oven chamber, air inlets at the sides of said oven chamber, an air outlet in the mid dle of said oven chamber, and means for causing a positive circulation of air through said chamber from each side upwardly toward the middle of the chamber and then downwardly to the outlet.

7 In an oven in combination, an extended oven chamber, air inlets at the sides of oven chamber, an air outlet in the middle of said oven chamber, said inlets and outlet being substantially co-extensive with the length of said chamber.

8. In an oven in combination, an extended oven chamber, air inlets at the sides of said oven chamber, an air outlet in the middle of said oven chamber, means for causing a positive circulation of air through said chamber from each side upwardly toward the middle of the chamber and then downwardly to the outlet and electric heating means located above said inlets for heating the incoming air.

In testimony whereof, I have hereunto subscribed my name this 27th day of November 1922-.

JAMES C. VVOODSON. 

